Feeding mechanism for sewing machines



Nov.'19, 1940. R. BECKER FEEDING MECHANISM FOR SEWING MACHINES Original Filed June 2, 1938 5 Sheets-Sheet l lllllllllllll NOV. 19, 1940. BECKER 2,222,017

FEEDING MECHANISM FOR SEWING MACHINES Original Filed June 2, 1938 s Sheets-Sheet 2 ymlllll' gvwwvtom RudoQokBec/ er Nov. 19, 1940. R. BECKER FEEDING MECHANISM FOR SEWING MACHINES Original Filed June 2, 1938 3 Sheets-Sheet 3 3mm Radaemh Beaifier Patented Nov. 19, 1940 UNITED STATES FEEDING MECHANISM FOR SEWING MACHINES Rudolph Becker, North Plainfield, N. J., assignor to The Singer Manufacturin Company, Elizabeth, N. J a corporation of New Jersey Original application June 2, 1938, Serial No.

211,345. Divided and 1939, Serial No. 286,546

16 Claims.

This application is a division of my application Serial No. 211,345, filed June 2, 1938.

This invention relates to sewing machines and more particularly to improved mechanism for 5 effecting movement of the work throughthe machine during the operation thereof.

An object of the invention is to provide an improved and simplified feeding mechanism for sewing machines, which is easy running and quiet in operation; in which vibration is reduced to a minimum; which is capable of being embodied in a substantially closed casing and therein subjected to continuous and automatic lubrication; and in which the work-engaging face of the feed-dog is maintained parallel with the worksupporting surface of the throat-plate during the entire work-advancing stroke of the feed-dog.

With the above and other objects in view, as will hereinafter appear, the invention comprises 0 the devices, combinations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, fromwhich the several features of the invention and the advantages 25 attained thereby will be readily understood by those skilled in the art.

In the accompanying drawings, Figure 1 is a front elevation, partly in section, of a sewing machine embodying the present invention.

30 Fig. 2 is a right end view of the machine shown in Fig. 1 with the hand-wheel and an end coverplate removed.

Fig. 3 is a horizontal sectional view taken substantially on the line 3-3 of Fig. 1.

35 Fig. 4 is an enlarged vertical sectional view substantially on the line 44 of Fig. 3.

Fig. 5 is a transverse vertical sectional view substantially on the'line 5-5 of Fig. 3.

Fig. 6 is a detail vertical sect1onal.view sub- 40 stantially on the line 6-6 of Fig. 3.

Referring more specifically to the drawings, the invention is disclosed as embodied in a sewing machine comprising a base I, standard 2, overhanging arm 3 and head 4. A main driving 45 shaft 5 is journaled lengthwise of the arm and carries at its rear end a combined beltand handwheel 6. At its forward end, the shaft 5 actuates', through suitable mechanism designated generally as I, a reciprocatory needle-bar 8 which 50 is mounted in the head 4 and carries, at itsv lower end, an eye-pointed needle 9. Also mount ed in the head 4 is a spring-pressed presser-bar III within the bifurcated lower end of which is secured, as by a clamp-screw II, the upright 55 shank I2 of a presser-foot I2. To enable the this application July 26,

presser-foot to be tilted relative to its supporting bar II, and to maintain the foot in its tilted position, the foot carries. opposed stop-screws I3 and I4 the heads of which are adapted to engage the opposite sides of the lower end I (I of 5 the presser-bar. By releasing the clamp-screw II and adjusting the stop-screws I3 and I4 the foot may be tilted relative to the bar I0 to cause either the toe-portion or the heel-portion to bear more heavily upon the work. After the desired 10 adjustment has been made, the foot may be secured to the presser-bar III by again tightening the clamp-screw II.

The base I, standard 2, arm 3 and head 4 are preferably formed as a single casting, the base 16 being in the nature of an inverted pan closed at the bottom by a plate I5 and gasket I6. The standard 2 is provided with a vertically arranged chamber I I within which operates a, belt I8 adapted to transmit rotary motion from a pulley 20 I9, secured to the main shaft 5, to a similar pulley 20 secured upon the rear end of a shaft 2I journaled horizontally in bearings 22 and 23 provided by the base I. To the unbroken upper surface I of the base I there is secured a hori- 25 zontally disposed work-supporting plate 24, one end of which is formed to receive the standard 2.

The end 2| of the shaft 2|, remote from the pulley 20, projects through a bore 25 formed in the vertical end wall I of the base I, and carries a conventional chain-stitch loop-taker 26 which cooperates with the needle 9 in the formation of stitches. Thus, rotation of the main shaft 5 effects reciprocation of the needle-bar and the needle carried thereby, and also, through 55 the belt I8 and pulleys I9 and 20, effects rotation of the loop-taker 26 in timed relation with the reciprocations of the needle.

Cooperating with the presser-foot to effect step-by-step movements of the work between successive reciprocations of the needle, is a feeding mechanism including a, feed-dog 21,which operates through a slot 28 in a throat-plate 29 secured in the work-plate 24. This feed-dog is adapted to be given 'backward-and-forward and rising-and-falling movements such as are common in conventional four-motioned feeding mechanisms. Power to effect these movements is taken from the shaft 2| by mechanism located wholly within an oil-tight chamber 30 formed by the inverted pan-like base I and the bottom plate I5.

As shown most clearly in Figs. 3 and 4, the feed-dog 21 is secured upon one end of a feedbar 3| by a screw 32 and held against turning relative thereto by having its shank 2! fitted into a slot 33 formed in a. disk 33. The disk 33 is secured to a head 3! formed integral with the feed-bar. The feed-bar 3% is journaled in a bore 35 in a horizontally disposed sleeve 35 formed integral with a depending rod 31. The rod 31 is slidingly mounted in a vertically arranged bearing sleeve 38 forming a part'of an oscillatory feed-rocker 39.' This feed-rocker is journaled upon a shaft 40 mounted in bushings 4i secured in the base I. Formed integrally with the feed-rocker 39 is a slotted segmental arm 42 adapted to have operatively connected thereto, by a stud 42*, the lower end of a pitman 43 having its upper end 43 embracing a crank or eccentric portion 44 formed on the shaft 2i. A portion of the stud 42 is fitted within a slot 42 in the arm 42. Thus rotation of the shaft 2i will, through the elements 44, 43, 42, effect oscillation of the feed-rocker 39 and thereby cause the feed-bar 3i and the feed-dog 21 carried thereby, to move back and forth transversely of the base I, thus giving to the feed-dog its feedand-return strokes.

The amplitude of movement transmitted to the feed-dog from the crank 44 is dependent upon the point of connection of the pitman 43 and stud 42 with the segmental arm 42. This point may be shifted, thereby to vary the stroke of the feed-dog, by the manipulation of a feed-adjust ing lever 45 pivoted upon a screw 46 at th right end of the machine (as viewed in Fig. 1) and projecting through a slot 41 formed in the forward wall of the standard 2 (see Fig. 2). Intermediate its ends, the lever 45 is connected by a link 48 to an arm 49 secured upon the rear end of a rock-shaft 50, journaled in the base I parallel to the shaft 2|. At its opposite end the shaft 50 carries an arm 5| which is connected, by a link 52, to the stud 42 which connects the pitman 43 to the segmental arm 42. It will be apparent that shifting of the lever 45 will vary the position of the stud 42 in the slot in the segmental arm 42 and thereby vary the feeding stroke transmitted to the feed-dog. The lever 45 may be secured in its various positions of adjustment by a clamp-screw 53 threaded upon the projecting end 45 of the lever 45 and adapted to engage a slotted cover-plate 54 secured upon the front face of the standard 2.

Rising and falling movements are transmitted to the feed-bar, in timed relation with its backward and forward movements, by a crank or eccentric portion 55 also provided by the shaft 2| (see Figs. 3 and 6). This crank is embraced by a block 56 having a bore 51 slidingly receiving one end of a bar 58. The other end of the bar 58 is slidingly mounted in a sleeve 59, pivoted, by means of a trunnion 6D, in a bearing block 6| secured in the end-wall l of the base I. Intermediate its ends the bar 58 is formed with an enlarged portion or clamp-block 62 having a transverse bore 63 adapted to receive the feed-bar 3| which is held against endwise movement therein by a set-screw 64 (see Figs. 4 and 6). The block 62 is split, as at 65 and a clampscrew 66 serves to draw the opposite sides together thereby to firmly grasp the feed-bar 3| therein. As the feed-rocker 39 is oscillated about the shaft 40 to give the feed-dog its feed-and-return movements, the bar 58 slides back and forth in the block 56 and the sleeve 59. Rotation of the crank 55 with the shaft 2| causes the bar 58 to be oscillated about the axis of the trunnion 60 and as the clamp-block 62, carried by the bar, embraces the feed-bar 3| it causes that element, and the feed-dog carried thereby, to be moved up and down, succes ively into and out of engagement with the work held upon the work-plate 24 by the presser-foot 12.,

Thus it will be apparent that the mechanism above described will give to the feed-bar 3| and the feed-dog 2? backward-and-forward and rising-and-falling movements such as are common to so-called four-motioned feeding mechanisms.

As shown most clearly in Figs. 3 and 4, the feed-bar 3! extends through an opening 68 formed in the end-wall l of the base I. This opening is of suflicient size to permit the feed-bar to have the necessary vertical and horizontal movements to give the feed-dog 21 the usual rising-and-falling and backward-and-forward movements common to four-motion feeding mechanisms.

In this type of feeding mechanism it is highly desirable that the work-engaging face of the feed-dog be maintained parallel with the worksupporting surface of the throat-plate during the entire feeding stroke of the feed-dog. That result has been attained in the present construction by merely arranging the bar 58 at an inclination relative to the work-supporting surface of the throat-plate 29 and work-plate 24, as seen most clearly in Fig. 6. With this construction, as the feed-dog is moved from front to rear to advance the work, its tendency to drop, after the feed-lift eccentric has passed through its uppermost position, is counteracted by the rising movement of the inclined bar 58 as it slides upwardly in the block 56 and sleeve 59,

To lighten the load on the feed-driving mechanism and to eliminate vibration in the machine, the feed-rocker has been balanced by means of a counterweight 51 attached thereto at the side of the axis of the rocker opposite the segmental arm 42. This counterweight statically balances the feed-rocker and therefore very little power is required to give to it its rocking movements. Likewise, during the running of the machine, the reactionary forces transmitted to the bearings (which forces heretofore have set up vibrations in sewing machines) are counteracted or neutralized with the result that the present machine may be operated at high speed with little or no vibration.

Having thus set forth the nature of the invention what I claim herein is:

l. A feeding mechanism for sewing machines comprising a drive shaft, a feed-rocker journaled on an axis substantially parallel to said drive shaft, a horizontally disposed feed-bar slidingly connected to said feed-rocker and arranged substantially parallel to said drive shaft, a feed-dog carried by said feed-bar and arranged transversely thereof, means to rock said feed-rocker thereby to give to the feededog its feed and return: movements, and means actuated by said drive shaft to effect vertical sliding movements of said feed-bar relative to said feed-rocker thereby to give the feed-dog rising and falling movements.

2. A feeding mechanism for sewing machines comprising a rotary shaft, an oscillating feedrocker journaled on an axis substantially parallel to said shaft, and provided with an upright bearing sleeve; a pin slidingly mounted in said sleeve and provided, at one end, with a transverse sleeve portion, a feed-bar mounted in said sleeve portion and arranged substantially parallel to said shaft, a feed-dog carried by said feed-bar and arranged transversely thereof, means actuated by said shaft to rock said feed-rocker thereby to give to the feed-dog its feed and return movements, and meansto move said feed-bar vertically thereby to giveto'the feed-dog rising and falling movements.

3. A feeding mechanism for sewing machines comprising a shaft, a feed-rocker journaled on an axis substantially parallel to said shaft, a member carried by said feed-rocker and having a pin-and-sleeve connection therewith to permit of vertical movements of said member on said feed-rocker, a feed-bar pivotally carried by said member and arranged substantially parallel to said shaft, a head on one end of said feed-bar, a feed-dog secured to said head and arranged transversely of said feed-bar, means to rock said feed-rocker thereby to give to the feed-dog its feed arid return movements, and other means actuated by said shaft to give to said member, feed-bar and feed-dog rising and falling movements.

4. In a sewing machine having a frame provided with an aperture in one wall thereof, a

feeding mechanism comprising a shaft, a feedrocker iournaled in said frame, a feed-bar carried by said feed-rocker and arranged substantially parallel to the axis of said feed-rocker, a portion of said feed-bar projecting through the aperture in said frame, a feed-dog carried by said feed-bar and arranged transversely thereof, a first means within said frame and actuated from said shaft to rock said feed-rocker thereby to give to the feed-dog its feed and return movements, a second means actuated from said shaft to' give to the feed-dog rising and falling movements, and auxiliary means for giving a rising movement to said feed-bar during a portion of the time said second means is tending to lower the feed-bar.

*5. A feeding mechanism as set forth in claim 4,

' in which the auxiliary feed-bar lifting means comprises an inclined bar slidingly mounted on the sewing machine frame and havlng'an operative connection with said feed-bar and with said feed-rocker, whereby movement of the feedrocker in one direction causes said slide-bar and feed-bar to be moved upwardly and rearwardly of the machine frame.

6. A feeding mechanism for sewing machines having a frame, comprising a feed-rocker pivothaving a frame, comprising a rotary shaft journaled in said frame, a feed-rocker pivotally mounted on said frame and having' an arm ex-' tending transverse to the' axis of the pivot, a feed-bar extending lengthwise of said shaft, a feed-dog connected with said feed-bar, a pinand-sleeve connection between said feed-bar and said feed-rocker, means actuated by said shaft and engaging said arm for oscillating said feedrocker to give to said feed-bar and feed-dog backward-and-forward movements, and means actuated by said shaft to give to said feed-bar and feed-dog rising-and-falling movements relatiye to said feed-rocker.

8. A feeding mechanism for sewing machines as set forth in claim 7 in which a counterweight is attached to said feed-rocker at the opposite side of the pivot thereof from which said arm extends.

9. A feeding mechanism for sewing machines having a frame,-comprising a rotary shaft journaled in said frame, a feed-bar, a feed-dog secured thereto, means actuated by said shaft for giving to said feed-bar backward-and-forward movements, a rotary eccentric actuated by said shaft for giving to said feed-bar rising-and-falling movements, and auxiliary means acting on said feed-bar to give to it a rising movement at the time when said eccentric initiates the downward movement of the feed-bar.

10. A feeding mechanism for sewing machines as set forth in claim 9, in which the auxiliary means for giving to the feed-bar a rising movement comprises an inclined slideway up which said feed-bar is moved during the forward move- 

